How do I restore these Library folders in Win 8 to working ones not flashing up error messages?

I too tried Vikrant Yadav's answer and it didn't work.

However, I discovered Method 1 works if you add one step.

1. Open File Explorer. 
2. DELETE ALL LIBRARIES that are having this problem.
3. Right click on "Libraries" and click "Restore Default Libraries".

If I took the (admittedly scary) step of deleting the libraries first (in my case it was all of them including an extra one I created for myself), "Restore Default Libraries" worked. For the default ones. I had to recreate my custom one.

Hi Kenneth,

Thank you for posting your query in Microsoft Community Forums.

This issue could be caused due to a corrupted system file. I would suggest you try these steps and check:

 To fix the issue I would suggest you to follow the methods provided.

Method 1: Restore default Libraries

I would suggest you try the restore library option and check if it helps. Please back up all the files in the library before trying this, just to make sure you don’t lose any files. Refer these steps:

a)      Open Windows explorer

b)      In the left panel, locate Library and right click on it

c)       Click “restore default libraries” option

d)      Check if the issue persists.

Method 2: Rebuild Index

Windows indexes all files and folder for accessing any files or folder. If the index file is corrupted, it may result in such issue often. So I would suggest you to rebuild the index and check. You can refer these steps:

a)      Press Windows key +F, type “index” in the search box

b)      Click on the settings tab below the search box and select the “indexing options” tile

c)       Check if the drive where you have installed the operating system is listed, if not click on the Modify button below

d)      Check the box against the drive and expand it to make sure that the “users” is selected

e)      Click OK to close the window

f)       In the Indexing options window, click on “Advanced” button and click “rebuild”.

Hope this helps. If the issue remains unresolved or if you have any further queries related to Windows, please get back to us and we’d be happy to help.